Abstract:

Cytochemical localization of nuclear-envelope nucleos-side triphosphatase was exhibited in the nuclear membrane and nuclear pores of the Necturus, maculosus oocyte. This enzyme is thought to promote nucleocytoplasmic transport of mRNA through the nuclear pores. Various tissue preparations were performed to assure optimum results of reaction product formation and preservation of tissue ultrastructure.Incubation of frozen oocyte sections in a modified Wachstein-Meisel medium resulted in positive staining of the nuclear membrane and the nucleoli as evidenced in light and electron micrographs. Whole oocytes were incubated in the Wachstein-Meisel medium and then embedded in Epon for electron microscopy. The whole oocytes contained reaction product associated with microvilli and plasma membranes. Exposure of manually isolated nuclei to the same experimental medium resulted in lead deposits in the nuclear envelope, the nuclear pores, and randomly dispersed among chromatin granules. Thus, these nuclear structures may play a role in transport of mRNA to the cytoplasm.